Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
A wireless communications network may include a number of network devices such as access points (APs) that can support communication for a number of wireless devices. A wireless device may communicate with a network device bi-directionally. For example, in a wireless local area network (WLAN), a station (STA) may communicate with an associated AP via downlink and uplink. The downlink (or forward link) refers to the communication link from the AP to the station, and the uplink (or reverse link) refers to the communication link from the station to the AP.
In WLANs, there may be cases in which multiple STAs are in communication with a particular AP. Access to the wireless medium may be controlled through a medium access control (MAC), which may allow different STAs to access a wireless channel according to enhanced distributed channel access (EDCA) rules. According to EDCA rules, STAs may be separated into groups with a transmit opportunity (TXOP), which is a duration of time slot during which STAs within the group are allowed to continually access the medium without backoff. In some deployments, a wireless network may have multiple different access priorities for each group and, within each group, priorities according to an access class of data that is transmitted using the wireless channel, each of which may have a different TXOP limit.
In order to enhance utilization of each time slot (or TXOP), EDCA based soft time division multiplexing (TDM) may provide for STAs within a group of STAs to access the wireless medium during a particular time slot. The STAs within the group may be permitted to access the wireless medium during the time slot at a priority lower than STAs in a second group. Alternatively, the STAs within the group may be permitted to access the wireless medium during the time slot at a priority higher than STAs in the second group. There is a need, however, to signal the appropriate operational parameters for each time slot, e.g., STA group identification information, EDCA parameters for each STA group, time slot information, etc., to the STAs within the group to ensure successful access during the appropriate time slot.